Yes, Katy Perry finally kissed a girl, but she didn't like it. Because Miley Cyrus decided to slip her that tongue of her's,

 Katy Perry says when she moved in for the staged peck with Miley in concert, Miley decided to shove her tongue down her throat. Katy pulled away in bacteriological horror:
“God knows where that tongue has been. We don’t know, that tongue is so infamous.”
Can we blame her? We'd be afraid too!